Lichenologist 35(2): 147-149 (2003) doi:10.1016/S0024-2829(02)00098-l Opegrapha cladoniicola, a new lichenicolous fungus from Hawaii Damien ERTZ and Paul DIEDERICH Abstract: A new species Opegrapha cladoniicola, lichenicolous on the podetia of Cladonia ochrochlora, is described from Hawaii. It is the first known Opegrapha species found growing on Cladonia. V 2003 The British Lichen Society. Published by Elsevier Science Ltd. All rights reserved. Key words: Cladonia, Hawaiian Islands, Opegrapha, Roccellaceae. Introduction While examining collections of lichenicolous fungi preserved in the herbarium of the University of Helsinki (H), we discovered a remarkable species of Opegrapha growing abundantly on podetia of Cladonia ochro- chlora. Since Opegrapha has not hitherto been known from Cladonia, and as our fun- gus is morphologically distinct from all other known lichenicolous Opegrapha species, the description of a new species is appropriate. Material and Methods Microscopical examination was carried out on hand cut sections mounted in water, 5% KOH (K), Congo Red with KOH pre-treatment, or Lugol's reagent without (I) or with KOH pre-treatment (K/I). Measurements and drawings of asci and ascospores were all made from material mounted in KOH. Drawings were done using a drawing tube. The Species Opegrapha cladoniicola Ertz & Diederich sp. nov. Opegrapha lichenicola insignis ascomatis atris, eprui- nosis, lirellatis, 180-500 x 110-160 urn, excipulo brunneo, K-, lateraliter 30-65 |im, hypothecio hyalino vel pallide brunneo, ascis subclavatis, 35- 44x9-14(^1X1, 6-sporis, ascosporis 3-septatis, 14- D. Ertz: National Botanic Garden of Belgium, Domaine de Bouchout, B-1860 Meise, Belgium. P. Diederich: Musee national d'histoire naturelle, 25 rue Munster, L-2160 Luxembourg, Luxembourg. 17 x 5-6 ^m, perisporo granuloso maturitate brunneo, conidiis 3-4 x 1 um. Typus: Hawaii, Lanai, Munro trail, Lanaihale, 1150 m, on fallen tree trunk, moist rain forest area, on Cladonia ochrochlora, 26 September 1966, Liisa & Mdkinen 66- 2146a (H—holotypus; hb. Diederich—isotypus). (Figs 1 & 2) Ascomata lichenicolous on the podetia of Cladonia, black, epruinose, lirellate, with a slit-like opening and a hardly visible disc, unbranched or slightly forked, 180-500 x 110-160 |am, aggregated in groups of often more than 10 ascomata. Exciple dark brown, K —, continuous below the hypothecium, laterally 30-65 ^m, basally 20-70 \im thick. Hypothecium hyaline to brownish, K —, 12- 23 |jm thick. Hymenium hyaline to brownish, K - , 1+ red (but upper part 1+ blue), K/I+ blue (only the hymenial gel reacting), 45- 75 |jm high; epihymenium brownish, K—. Paraphyses branched, anastomosing, 1-2 |jm thick, apically not or indistinctly swollen. Asci subclavate, usually 6-spored, 35- 44x9-14 Jim, wa ll I-, K/I-, except for an apical K/I+ blue ring. Ascospores hyaline, becoming brown at maturity (pigment located in the perispore), elongate ellipsoid, 3-septate, slightly constricted at the median septum, 14-17 x 5-6 \ivn; perispore present, with a coarsely verrucose to granulose pig- mentation when mature. Pycnidia not uncommon, black, immersed, 35-50 |xm 0024-2829/03/020147 + 03 830.00/0 < 2003 The British Lichen Society. Published by Elsevier Science Ltd. All rights reserved.